Computers Could Infect a USB Device’s Firmware It enables the creation of malicious devices that can pretend to only be one type of device, but also be other types of devices. This is just a fundamental issue with USB itself. It could function as a normal flash drive while reserving the right to do other things. A USB flash drive could claim to be a flash drive, a keyboard, and a USB Ethernet network adapter when you insert it.

Importantly, USB devices can have multiple profiles associated with them.

RELATED: Not All 'Viruses' Are Viruses: 10 Malware Terms ExplainedĪ modified storage device could function as a boot device when it detects the computer is booting, and the computer would then boot from USB, loading a piece of malware (known as a rootkit) that would then boot the real operating system, running underneath it.

A phone or any type of USB device with its own Internet connection could use that connection to relay information from your computer. A connected device could function as a USB Ethernet adapter and route traffic over malicious servers. More sneakily, a USB flash drive could appear to function normally, but the firmware could modify files as they leave the device, infecting them. Thanks to keyboard shortcuts, a malicious firmware functioning as a keyboard could-for example-open a Command Prompt window, download a program from a remote server, run it, and agree to a UAC prompt. When you connect it to your computer, it could send keyboard-press actions to the computer as if someone sitting at the computer were typing the keys. For example, a USB flash drive with malicious firmware could function as a USB keyboard. The key to this problem is the design goal that USB devices could do many different things. It’s the code running the device itself, and there’s no real way to check for and verify a USB device’s firmware is safe. This firmware itself isn’t actually a normal piece of software that your computer has access to. A USB keyboard’s firmware would convert physical key-presses on a keyboard to digital key-press data sent over the USB connection to the computer. For example, a typical USB flash drive firmware would manage transferring the files back and forth. These USB devices-and other components in your computer-run a type of software known as “firmware.” Essentially, when you connect a device to your computer, the firmware on the device is what allows the device to actually function.

Usb security flash